An amperometric glucose sensor with combined enzyme layers.

An amperometric needle-type glucose sensor consisting of a silver tube as the cathode and a platinum wire as the anode was developed. The sensor was provided with two enzyme layers (glucose-oxidase and catalase) separated by a polyurethane membrane. The catalase caused an accelerated decomposition of H2O2 generated during the enzymatic oxidation of glucose. In this way the lifetime of the sensor and the oxygen dependence of the analytical signal could be improved.